- Lens focal length doesn't change between formats. Focal length is the property of the lens, NOT the format!
OTOH, as a side note, image circle / coverage requirements change between formats and this fact has to be taken into account when using lenses at different film formats, specifically in the case you plan to use a lens on a larger format. (Since you're currently reducing the format, image circle won't be a problem in your case; because the lens covers / was designed for a larger area than what is needed for the 35mm format...)
- A 150mm MF lens mounted on a 6x4.5 camera will give the equivalent (diagonal) field of view of a 92mm lens mounted on a 35mm camera. (I think this is where people got confused; what changes between formats is the field of view, again, not the focal length!)
- A 150mm MF lens will give the equivalent field of view of a ...SURPRISE!!!... 150mm lens when mounted on a 35mm camera!
Hope this helps & thanks for the funny thread!
Last edited by Loris Medici; 10-21-2010 at 12:05 PM. Click to view previous post history.